Programmers contributing to code for an evolving software product often do so in collaboration with many other parties. As such, they may be creating code in a public or collaborative kind of space for credit, creativity, debugging, and reward. Currently, there is no single fair way to measure or to determine the contribution of programmers in a public, or even in a private, space. There is accordingly a need for a secure and robust approach to track and to append information related to collaborative coding for the purpose of credit, reward, and dispute resolution, and for other purposes.